Thursday, April 26, 2012

[This is an updated and edited version of a post originally published in February 2011. I'm updating it as the original post referred simply to a poster presentation but yesterday the full article was published ahead of print in the Journal of Clinical Endocrinology and Metabolism]

Talk about setting people up for long term struggle.

The term metabolic adaptation is given to the phenomenon whereby when a person loses a certain percentage of weight, their metabolisms slow by greater amounts. This process may be theoretically accelerated with more rapid weight loss as a consequence of the rapidly losing body metabolizing calorie burning muscle along with fat to make up for its massive energy deficit.

And as far as rapid non-surgical weight loss goes, there's probably no weight loss program more rapid than that of the television show The Biggest Loser, where it’s not uncommon for contestants to lose upwards of 150lbs at an averaged pace of nearly 10lbs a week.

Of course what’s different about the Biggest Loser as compared with most other non-televised rapid weight loss programs is the incredibly large amount of exercise concurrently involved, along with an almost certainly severe degree of stress, peer pressure and dietary restriction given the team and competitive nature of the show (where the team who loses the least weight has a member voted off, and where the last man or woman standing wins $250,000).

So is the weight lost on the Biggest Loser, a show now formally endorsed by the First Lady as an inspiration to the nation, healthy? Does the huge amount of exercise protect contestants against the show doing marked damage to their metabolisms?

The answer to both of those questions certainly appears to be, "No".

In an article published yesterday ahead of print, Darcy Johannsen and friends studied the impact 7 months of Biggest Loser weight loss had on the resting and total energy expenditures of 16 participants. They used all the latest gadgets to do so including indirect calorimetry and doubly labeled water. So what happened? By week 6 participants had lost 13% of their body weight and by week 30, 39%. More importantly by week 6 participants metabolisms had slowed by 244 more calories per day than would have been expected simply as a function of their weight loss and by week 30, by 504 more.

That's basically a meal's worth of calories a day that Biggest Loser contestants no longer burn as a direct consequence of their involvement. How do you think you'd do at maintaining your weight if you ate an extra meal a day?

But maybe that's typical. After all, metabolic adaptations are a known consequence to weight loss - couldn't that be all we're seeing here? I guess it's too bad there's no control group the study could have used for comparison.

Actually there kind of is. Bariatric surgery patients lose massive amounts of weight in a hurry as well, and they generally do so without the inane extremes of lifestyle endorsed by the Biggest Loser. If there were a study on the impact bariatric surgery losses had on resting and total energy expenditure, that would certainly offer some insight as to the healthfulness of Biggest Loser's weight loss program.

Good news! There is such a study. Published in 2003 in the American Journal of Clinical Nutrition researchers looked at the impact bariatric surgical losses had on the resting and total energy expenditures of 30 men and women whose pre-operative average BMIs of 50 were within 1 point of the Biggest Loser contestants' averages of 49, and who lost a Biggest Loser style average of 117.5lbs. And guess what? While resting energy expenditure indeed was shown to slow, it didn't slow down in excess of what would be expected by weight loss alone. In other words? Looking at these two studies, Biggest Loser style weight loss destroys metabolisms dramatically more than does bariatric surgery and does so in huge excess of what would be expected simply as a consequence of losing weight (though I suppose to be fair, the study on the surgical patients was done at 14 +/- 2 months, while the Biggest Losers' was at 7 - perhaps the Losers' metabolisms will improve with time)

That's a rather ironic finding given that one of the Biggest Loser study's authors, Biggest Loser's TV doctor Dr. Robert Huizenga, regularly trash talks bariatric surgery on the show as a terrifically unhealthy way to lose weight. Metabolically speaking, it would seem to me that his own study would suggest bariatric surgical weight loss is far healthier to a body's metabolism than is Biggest Loser style loss.

The study concludes,

"Unfortunately, fat free mass preservation did not prevent the slowing of metabolic rate during active weight loss, which may predispose to weight regain unless the participants maintain high levels of physical activity or significant caloric restriction"

Gee, ya think? "May"?

Here's how I'd spell it out. While some contestants of the Biggest Loser will translate their new lifestyles into careers as product spokespeople or fitness trainers and hence have new external motivators to maintain their extreme behaviours, those who don’t are doomed by the show itself to regain their weight, as the lifestyles promoted by the reality television show The Biggest Loser are only "realistic" to those whose livelihoods and/or fame depend on them.

Case in point? That picture up above, that's Eric Chopin. He was the winner of the third season of the Biggest Loser. He lost just over 200lbs. A few years later he was on Oprah to talk about his massive regain. Think Eric dropped the ball? Not me. I think the Biggest Loser provided him with a nonsensical and metabolically dangerous approach to weight management, and in the process, stacked his deck entirely against him.

[UPDATE: Received a thoughtful email from obesity researcher Dr. Jennifer Kuk who wondered whether or not the Biggest Loser subjects had their energy expenditures measured in the week or days leading up to the finale. If so, she feels (and I'd agree) that given the competition they might have all been severely under eating so as to increase their chances of winning, and that it therefore might have been their temporary under feeding that led to their abysmal energy expenditure results.]

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About Me

Family doc, Assistant Prof. at the University of Ottawa, Author of The Diet Fix, and founder of Ottawa's non-surgical Bariatric Medical Institute - a multi-disciplinary, ethical, evidence-based nutrition and weight management centre. Nowadays I'm more likely to stop drugs than start them. You can also find me on Twitter and Facebook.

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